Does an appraiser count a detached guest house as part of value?

[Evan Rochford]

Converting a 2 car detached garage into a guest house.  After it is done is it possible to get a cash out refinance for the added value to use the money towards another project? Will the appraiser count any of the remodel done to converting the garage to a guest house?   Or since it is detached this will not count towards added value when it comes to what an appraiser looks for when reporting what he thinks the property is worth?